In many areas of technology, user interfaces (HMI short for “human machine interface”) are used for interacting with machines and equipment, wherein graphical user interfaces, or respectively user interfaces (GUI short for “graphical user interface”) are now widespread. Graphical user interfaces can be used to depict, select and operate complex graphical elements on a screen surface. Operation can be carried out by a plurality of different input devices, such as by touching a touch-sensitive display surface, a so-called touchscreen.
With GUIs that have an extensive scope of functions, or respectively a plurality of functionalities, the number of graphic and/or control elements can be so large that they cannot all be effectively displayed simultaneously. The danger also exists that the comprehensibility and usefulness of the GUI will suffer from displaying a plurality of graphic and/or control elements. This can for example be problematic when GUIs are used in vehicles. Consequently, with a GUI intended for the driver of a vehicle, the representation of information and operation should be as simple and intuitive as possible, in particular while driving, to minimize distraction from the task of driving and ensure driving safety.
Although the driver in most driving situations is interested in a compact representation of information, there are also cases in which he desires more comprehensive or detailed information. Normally, the driver must make control entries to switch from a representation of information to another one with more details. This can be accomplished by pressing a button, executing a gesture, or by voice commands. Alternatively, this can also occur automatically. For example, the direct environment can be enlarged in a driving maneuver in a navigation application and then minimized after the driving maneuver.
From the prior art, it is known to provide a viewing-direction-dependent display device to simplify interaction with the GUI for the driver. For example, DE 10 2013 015 634 A1 describes detecting the viewing direction of a driver of a motor vehicle in order to activate an interactive mode when the driver looks at one of several display regions of a display apparatus, at least for a given duration of a glance. In this context, the interaction mode is maintained as long as a control of the display apparatus is not terminated, or another predetermined criterion has not been satisfied.
EP 2 390 139 A1 also discloses detecting the viewing direction of the driver to determine which of several possible areas of interest he is viewing. This area is first illuminated more weakly and then more strongly while viewing over a specific period.
DE 10 2007 025 531 A1 likewise discloses a viewing-direction-controlled display system for a motor vehicle in which the viewing direction of the driver is detected and the duration of the detected viewing direction is determined, wherein information is depicted depending on the duration of the viewing direction, and possibly also depending on the urgency of perceiving the depicted information.
DE 10 2012 006 966 A1 discloses that the viewing direction of the driver is detected in order to determine a control panel on a display surface viewed by the driver, and to trigger an associated function that be can be executed by the vehicle.
Finally, DE 10 2013 210 354 A1 discloses a view-controlled interaction with images on data glasses worn by the driver of a vehicle. In this context, the viewing direction of the driver is detected, and it is determined whether the viewing direction points toward a display area with an activation element on the data glasses. If this is the case, content assigned to the activation element is depicted on a display area that is larger than the display area of the activation element.